The goal of the research herein proposed is improvement of drug therapy in epilepsy and conditions requiring analepsis. To this end the effects of convulsant and anti-convulsant drugs on single neurons are being studied by electrophysiological means in an effort to associate differences in drug responsiveness with differences in the physiological, biochemical and anatomical characteristics of the cells. Cells with certain characteristic drug responses are being studied further with ion-specific intracellular electrodes. The information thus gained is expected to narrow the range of cellular mechanisms on which it is probable that particular drugs exert actions of physiological consequence. Because technical factors restrict intracellular neurophysiological study of drug actions in higher nervous systems, and because of the likelihood that many cellular mechanisms vulnerable to neuropharmacological agents are widely distributed among the phyla, use is being made of invertebrate neurons, particular cells being chosen for the extent and precision of the physiological, biochemical and anatomical information available about them.